Hmm, because of the size of your room, I think you'd be better off buying a decent system of a receiver and speakers. Here's what I would recommend:
Pioneer 815k from
J&R: $250 shipped (you have to call their toll free number).
2pr BIC DV62si bookshelves from
Amaon: $231.80 Shipped
1 BIC DV62CLR Center from
Amazon: $104.99 shipped
Hsu STF-1 from
Ascend: $311 shipped
150 ft. Belden 5000UE 12ga Speaker Cable from
Westlake: $31.50 PLUS SHIPPING
5pks
Impact Acoustics Banana Plugs: $14.95 PLUS SHIPPING
For any other interconnects, check out
Parts Express,
Impact Acoustics and
Knu Konceptz.
This is a complete system. Another option would be to opt for just a pair of nicer main speakers and a better receiver and slowly build your system from there. If you decide to go this route, then it might be best to start auditioning some speakers in the $500-$700 range at your local hi-fi shops. There are plenty of Internet direct brands in that range, such as speakers available from
Ascend,
Axiom, and
AV123.